Posts about Core Capacity

Why does Metro have budget problems? Why is traffic bad? While there are many reasons, this map shows the biggest one: Our region keeps growing mostly on one side, which taxes strained transportation networks and wastes resources.

This map shows projected growth around the region. There's a stark line between all the highest-growth areas, in the west, and lower growth to the east. The folks at PlanItMetro, who made this map, wrote:

Between 2020 and 2040, the region expects to add about 870,000 more jobs (25% increase) and 1 million more people (16% increase). As shown in the map below, much of that growth is planned where transit is already at or exceeding capacity, while many other areas that have high-quality transit continue to be underdeveloped. The result: more congestion.

These stats were part of a big new study, called ConnectGreaterWashington. Last weekend, I wrote about the broad strokes in the Washington Post. The key takeaway: Our region is not growing enough in areas, mostly on the east side of the region, where there's already ample transit (and road) infrastructure, while the growth that is happening is straining the infrastructure we have.

There's a real price tag for this.

Unbalanced growth costs money

In the ConnectGreaterWashington study, WMATA planners modeled several scenarios. With no particular change in our current path, Metro will have crush loaded trains (which are not just uncomfortable but more often delayed) on the Orange/Silver lines west of Rosslyn and the Yellow/Green lines south of L'Enfant. Meanwhile, its operations will cost local governments $350 million a year by 2040 (up from about $245 now) in subsidy.

Just making the areas around stations more walkable and bikeable and changing fares to encourage off-peak travel helped only a tiny bit on its own. Shifting predicted growth between 2020 and 2040 inside individual jurisdictions, from places far from transit to places near, helped more, but the crowding imbalance on Metro (and roads), where trains (and highways) are packed in one direction and nearly empty in the other, didn't change.

Metro could be profitable! Or, at least, closer to it

There was a scenario which fixed myriad problems: Rebalancing growth more evenly across the region from 2020 to 2040. If the region focused enough of its economic development efforts where there is underused transportation capacity, Metro could even run a surplus of $270 million a year. That's a revenue stream WMATA could bond against for fixes like a second Rosslyn station to relieve Blue Line crowding (costs about a billion), walkways between downtown transfer stations (similar), or all eight-car trains (about $1.7 billion).

Those fixes would be even more needed than they are today, as under this scenario, Metro would also need more capacity. And I wouldn't oversell the chance that Metro becomes "profitable"—it probably requires more shifting of growth than most governments, employers, or developers are willing to go for.

Besides, it's not clear that running a surplus is what a transportation system ought to plan around. We build transportation systems to move people, and they cost money. Many European cities happily spend much more on their transit systems, because they find them valuable and are willing to invest in public works projects. It's worthwhile to have transit even if its ridership isn't astronomically high.

The hole will just get deeper

However, we need to recognize that for every year the western edge of the region grows much faster than the east side, we're digging a bigger hole. New COG projections, which come from local governments' own growth plans and aspirations, estimate that Loudoun and Prince William will add 100,000 jobs each by 2045, or 75% more than they have today. Meanwhile, the forecast estimates Prince George's will just gain 19% more jobs and 10% more residents.

For every year that kind of pattern continues, we're making Metro more expensive, fiscally, than it needs to be and making the challenges of crowding on roads and rails worse. This is costing every jurisdiction and taxpayer far more than it should, including those on the west side of the region.

Or, to put it more starkly: Even Virginians and western Montgomery residents pay every day for the lack of growth in Prince George's, and it's in their interests as well as everyone else's to better balance our growth.

Metro's planners have been studying ways to deal with the capacity crunch at Rosslyn station. A track connection from Court House to Arlington Cemetery isn't possible, but a second station for the Blue Line is, and could be built by 2025.

Each Metro track segment is limited to 26 trains per hour (TPH). At Rosslyn, where the Blue, Orange, and (soon!) Silver Lines come together, this limits the number of trains on each line. In 2012, Metro reduced the number of Blue Line trains to allow more Orange Line capacity. Later this month, the number of Blue Line trains will decline even more to make room for the Silver Line.

Two possible fixes for Rosslyn. Image from WMATA.

There's really no way to alleviate this crunch without additional track capacity. Eventually, it's likely that a second subway across downtown will be necessary to handle the ridership. Metro is currently exploring the idea of building a new loop line through the central city. A new subway would allow Orange and Silver lines to each have 13 slots, and the Blue Line could also to have increased service up to 13 TPH.

Earlier, Metro was looking at two ways to address the capacity constraints. One concept was a "wye" track connection, to allow trains coming from Court House to turn south and go toward Arlington Cemetery and vice versa. The follow-up study this year, though, determined that building foundations make this option impossible.

Potential location for a second Rosslyn station. Image from WMATA.

The other option, though, is feasible. It would require building a second station one block west of the current Rosslyn station. This new platform would connect to the existing Rosslyn station with a pedestrian tunnel. At least initially, only the Blue Line would use it. The Orange and Silver lines would stay in the current station.

If built, this would mean that the Blue Line would only operate between Franconia-Springfield and Rosslyn (though some Yellow Line trains might still start and end in Franconia as they do today). That would mean that, at least until the line is extended across the Potomac, Blue Line riders would need to transfer to an Orange or Silver line train at Rosslyn to get downtown. But all the lines at Rosslyn would be coming more frequently than they do today, which might alleviate the inconvenience of changing trains.

These diagrams I made last year show how the new station (and the infeasible wye) could work.

Note: Since this graphic was created in 2013, Metro has announced there will be 5 TPH per hour on the Blue Line once the Silver Line opens, rather than 6 as shown here.

The wye would have allowed for more trains on the new Silver Line tracks and given riders from Alexandria and south Arlington a one-seat ride to Court House, Clarendon, etc. (if they caught the train every ten minutes going that way), but it also would have made service more complex, added chances for delays, and not fit in as well with a future Potomac River crossing. A new Rosslyn terminal would hopefully be just the first segment of a crosstown subway through Georgetown.

Possible extension to Georgetown.

Right now, Metro's planning staff is recommending the proposed station be moved forward for project development funding, which essentially means that they want it to get money for more detailed study. But the project is in the Metro 2025 plan, so planners anticipate that this could be opened within 11 years—if the jurisdictions, particularly Virginia and its cities and counties, are willing to pay for it.

For the next few years, the capacity crush at Rosslyn is likely to get worse. But this project might be the light at the end of the tunnel for Blue, Orange, and Silver line riders.

With Silver Line opening soon, Metro is reducing the number of Blue Line trains running between Pentagon and Rosslyn. Reader Daniel W. wants to know why Metro is doing this.

Photo by Adam Fagen on Flickr.

Could GGW offer some insight into why Metro is increasing headway on the Blue Line instead of clearing room in the tunnel by running fewer Orange Line trains but running them with eight cars? WMATA can service the same number of Orange Line riders with one third fewer trains by simply running trains at system capacity.

The current situation is fairly complex. Each Metro line has a capacity of 26 trains per hour (TPH). Right now, the combined Blue/Orange line between Rosslyn and Stadium/Armory is operating at that limit. When the Silver Line starts operating later this month, both the Blue and the Orange lines will see fewer trains to make way for the Silver Line. That much is inevitable.

But the Blue Line reduction is more severe for two primary reasons. First, there's simply more demand for trains coming from north Arlington, so Metro wants to give the majority of the slots to the Orange and Silver lines. The other reason is that the line coming up from Alexandria and southern Arlington splits at Pentagon. Blue and Yellow line riders have two options for getting into downtown. But for the Orange and Silver lines, the only place they can be routed is via Rosslyn.

Many Blue Line riders are understandably upset about having longer waits for a direct train to the western part of downtown. Now, it may often be faster for riders to take the "rush plus" Yellow Line from Franconia and transfer at L'Enfant. But without a separated subway for the Blue Line, there's not much WMATA can do to increase capacity.

Comparing capacity

What does the current breakdown look like?

View peak service levels:
Pre-Silver LineWith Silver LineNote: This graphic was originally created in 2013. Since then, Metro has announced there will be 5 TPH per hour on the Blue Line once Silver opens, rather than 6 as shown here.

Right now at Rosslyn during peak hours, there are 19 inbound Orange Line trains and 7 inbound Blue Line trains each hour. That means there's an inbound train about every 2 and a half minutes.

Of the Orange Line trains, about 40% are 8 cars long and 60% are 6 cars. All of the Blue Line trains are currently 6 car trains. That means that each hour at Rosslyn, there are roughly 42 inbound Blue Line cars and 130 inbound Orange Line cars. This means a total of 172 inbound cars per hour.

Once the Silver Line opens, the distribution will change. Starting on July 28, the mix at Rosslyn will be 11 Orange Line trains each hour, 10 Silver Line trains per hour, and 5 Blue Line trains per hour.

All of the Silver Line trains will be 6 cars in length. The proportion of Orange Line cars is not expected to change, so it will remain about 40% 8-car trains. The Blue Line will operate with half of its trains as 8 car sets.

That means that at Rosslyn, there will be 35 Blue Line cars inbound each hour, a reduction of 7 cars. The Orange Line will also see a reduction, with only 74 cars per hour. The Silver Line will have 60 cars inbound each hour. Now, since the Silver and Orange share in northern Arlington, riders at stations like Clarendon will see 134 inbound cars each hour, which is a very slight increase. Overall, at Rosslyn, that will mean 169 cars inbound each hour (which is a slight decrease).

So, even though the transit agency is reducing Blue Line frequency in order to fit more trains coming from northern Arlington, the change in the length balance of those trains means that essentially passenger capacity is staying the same. It's only increasing by 4 cars per hour. And of course, it's dropping by quite a bit for the stations on the Orange Line west of East Falls Church (from 130 today to 74), though that section of the line is less crowded than the parts closer to the core.

Alternate solutions

Daniel's question is specifically whether WMATA can have the same capacity by increasing the length of Orange Line trains rather than reducing frequency on the Blue Line.

If WMATA kept the same number of Blue Line trains as there are today—7 TPH each 6 cars in length—the inbound Blue would have 42 cars per hour. The number of Orange Line trains would still have to change to accommodate the Silver Line, so let's assume the remaining 19 slots are distributed 10 to the Orange Line, with all 8-car trains, and 9 to the Silver Line, with all 6-car trains.

There would then be 80 inbound Orange Line cars per hour and 64 inbound Silver Line cars per hour, for a total of 144 cars per hour coming through northern Arlington. That would mean a total of 186 cars per hour inbound at Rosslyn, which is significantly more than today.

However, this solution would actually require Metro to use more cars in daily service, and right now, there simply aren't enough. The Silver Line requires more cars to run, since Wiehle Avenue is so far out. The opening of the new line is already stretching Metro's fleet. There will be more wiggle room sometime soon, once the first 64 7000-series cars arrive, but that milestone is probably more than a year away.

The other issue is that Metro still needs upgrade power systems on all the lines to enable more 8-car trains to operate. Right now, even if Metro had enough cars, there isn't enough traction power capacity to run all 8-car trains, though the agency is slowly working to upgrade traction power substations throughout the system.

Metro does anticipate running 100% 8-car trains in the near future. But being able to do so is dependent on being able to finance more 7000 series railcars. Right now, the local jurisdictions—who pay for capital upgrades—haven't ponied up enough money for that to happen, but there's still time.

WMATA expects ridership to continue to grow. More people ride the Orange Line in northern Arlington than ride the Blue Line between Pentagon and Rosslyn, and so the transit agency is trying to send enough trains that way. Officials see a Blue Line reduction as the only way right now, and since the Yellow Line bridge offers a relief valve, Metro can still give Blue Line riders just as many inbound trains each day, but some riders who used to have a direct trip may find themselves making a transfer.

The only way to resolve this capacity crunch is, in the short term, for local governments to fund more railcars and more power stations, and eventually build another Potomac crossing. Without a new river crossing, there can't be more trains on Blue, Orange, and Silver at the same time.

One of the challenges of adding in a new crosstown line where one was never envisioned is dealing with transfers.

It's absolutely essential that Metro get these transfer stations right. Today, Gallery Place is a nightmare due to its flawed design. That station was designed with two major flaws. The off-center meeting of the Green and Red Lines is due to the Red Line swinging south to Judiciary Square. The narrow platforms are because of the historic art museum upstairs. We're still paying for a design decision made 40 years ago, and it really illustrates the need to get it right this time.

Metro's loop proposal is still very nebulous because it's so early in planning. Much could change. But the conceptual alignments shown in their map suggest the potential for inefficient transfer stations.

Building better transfer stations

At Waterfront, for example, the Green Line follows M Street. The proposed loop would run under Eye Street, 3 blocks north. Right now, riders from Alexandria and South Arlington have a straight shot on the Yellow Line to the 7th Street subway and the eastern side of downtown.

See the Waterfront station under:
Eye StreetM Street. All graphics by the author.

If the new loop station is built at 4th and Eye, those riders will have to walk over 1,000 feet to change from the Yellow to the Green. That's as long as the walk from Metro Center to Gallery Place. The additional inconvenience and time it takes to transfer will make transit less competitive for many riders. And it may create future crowding issues, like those faced at Gallery Place.

Locating the new station adjacent to the existing Waterfront stop would make transferring much easier and less time-consuming. And that would be a boon for many riders, especially those who would need to transfer under the new scheme, like anyone who takes the current Yellow Line from Virginia to downtown DC.

There's an even better solution than just building the new station next to the old one: Build a new station for the Green Line and the loop line.

A four-track design like the one above would make transferring very easy. Many riders wouldn't even need to use an escalator. Inbound trains would be on one level and outbound trains would be on another. This is exactly like the design of the Lionel-Groulx transfer station in Montreal.

This would probably not be possible as a reconstruction of the existing Waterfront station, but would probably need to be new construction adjacent to the current stop.

In this design, a commuter riding from Suitland to Union Station could simply exit her Green Line train at Waterfront and walk across the platform to board a Loop train on the outer loop headed toward Capitol South and Union Station.

Similarly, a person commuting from Huntington to Archives could get off his Yellow Line train at Waterfront and just walk right across the platform to a waiting Green Line train headed toward L'Enfant and Gallery Place.

Similar situations exist where the proposed loop line crosses the Red Line. Metro's proposal seems to keep the new line under H Street near Union Station and under M Street where it crosses Connecticut Avenue.

The Red Line is currently Metro's busiest line, and it provides access to many destinations. Forcing riders to make long walks is inefficient, and if the tunnels deposit riders at one end of the platform, a situation similar to the one at Gallery Place is likely to arise again.

The transfer at Farragut North/Longfellow isn't as bad as the potential one at Waterfront. But the walk between the stops would still be almost 750 feet. Instead of keeping the line under M Street, the loop could swing down Vermont Avenue to either K or L Street. That would allow a much shorter transfer between the Red Line and the Orange Line as well.

See the Farragut station under:
M StreetK Street

At Union Station, Amtrak has grand plans to expand the station and create a second front along H Street on the north side of the complex. In that regard, Metro's loop wouldn't be too inconvenient to commuter and Amtrak trains. Of course, if the redevelopment of the station doesn't happen, riders would have a less pleasant trek to connect to their trains.

But the walk to connect to the congested north end of the Red Line platform is over 600 feet. And that means that riders connecting to trains bound for Metro Center or Silver Spring would also have an inconvenient transfer.

Locating the new loop station on the south side of the station, under Massachusetts Avenue, could make transfers much easier, and it wouldn't sacrifice access to commuter or Amtrak trains either.

See the Union Station station under:
H StreetMassachusetts Avenue

The Massachusetts Avenue alternative also seems to make it easier to extend the M Street subway east across Capitol Hill and/or the 2nd Street subway up North Capitol Street should future demand warrant that expansion. Ideally, the station under Massachusetts Avenue would include 4 tracks and 2 platforms so that if the loop were split into an east-west and a north-south line trains wouldn't have to share tracks.

Tradeoffs

One of the bigger tradeoffs is the discussion of whether increasing the area within a 5 or 10 minute walk of transit is more important than easy transfers.

For example, if the new loop line is pulled down to K Street at Farragut Square, the West End station would be farther south, closer to the existing Foggy Bottom station. That means that less new territory would be within a 5 minute walk of Metro. On the other hand, essentially all of the West End is already within a 10 minute walk of Metro.

Compare some alternatives below. Note that the tan and gray areas are within 10 and 5 minute walks of existing stations. Light pink areas would be new areas within 10 minutes of Metro and dark pink areas would be new areas within 5 minutes of Metro.

Walksheds from existing stations.

Walksheds from Metro's loop proposal.

Walksheds from a K Street/Mass Ave alternative.

Better transfer stations could mean fewer headaches for future commuters. But it might also mean less area is available for new development in the core, lowering tax revenues for the District. Co-locating stations is also likely to be more expensive and disruptive to riders. But in many cases, it may well be worth it. It's certainly worth having the discussion.

Maryland and Virginia will both enact major new transportation funding bills this year. Neither bill says exactly which projects will be funded, but here are the top 10 projects in Maryland and Virginia that most deserve to get some of the funds.

Tysons grid of streets, no. 2. Image from Fairfax County.

1. 8-car Metro trains: Metrorail is near capacity, especially in Virginia. More Metro railcars and the infrastructure they need (like power systems and yard space) would mean more 8-car trains on the Orange, Blue, and Silver Lines.

2. Tysons grid of streets: Tysons Corner has more office space than downtown Baltimore and Richmond put together. Converting it to a functional urban place is a huge priority.

3. Purple Line: Bethesda, Silver Spring, Langley Park, College Park, New Carrollton. That's a serious string of transit-friendly pearls. The Purple Line will be one of America's best light rail lines on the day it opens.

4. Baltimore Red Line: Baltimore has a subway line and a light rail line, but they don't work together very well as a system. The Red Line will greatly improve the reach of Baltimore's rail system.

5. Silver Line Phase 2: The Silver Line extension from Reston to Dulles Airport and Loudoun County is one of the few projects that was earmarked in Virginia's bill, to the tune of $300 million.

6. Arlington streetcars: The Columbia Pike and Crystal City streetcars both have funding plans already, but could potentially be accelerated.

7. Route 7 transit. Leesburg Pike is the next Rosslyn-Ballston corridor waiting to happen. Virginia is just beginning to study either a light rail or BRT line along it.

8. Corridor Cities Transitway: Gaithersburg has been waiting decades for a quality transit line to build around. BRT will finally connect the many New Urbanist communities there, which are internally walkable but rely on cars for long-range connections.

Corridor Cities Transitway, no. 8. Image from Maryland MTA.

9. MARC enhancements: MARC is a decent commuter rail, but it could be so much more. Some day it could be more like New York's Metro North or Philadelphia's SEPTA regional rail, with hourly trains all day long, even on weekends.

Yesterday, we discussed how Metro could grow its core capacity if it chooses to build a Rosslyn wye in the short run. Today we'll look at how a terminal for the Blue Line could fit into the picture.

Photo by tracktwentynine on Flickr.

Today, Rosslyn is the biggest bottleneck in the system, which will only get worse when the Silver Line opens. Three lines vie for space in one tunnel from Rosslyn eastward, which limits trains on the Blue, Orange, and Silver Lines.

Metro could relieve the pressure for now by either building a new terminal for the Blue Line at Rosslyn, or a "wye" to let some trains from Tysons go to Arlington Cemetery and farther south in Virginia. But in the long run, Metro needs more capacity over the Potomac River.

Post-2025 solutions with a Rosslyn terminal

The Rosslyn terminal would enable Blue Line trains to terminate at Rosslyn without interfering with the Orange or Silver Lines. This would allow more Orange and Silver trains from Tysons and the Rosslyn-Ballston corridor. But it also means that all Blue Line riders going to DC would need to transfer at Rosslyn or Pentagon.

That solution might work for a few years, but if Metro ridership continues to grow, the Rosslyn terminal would need to become the first phase of a new Potomac crossing.

A separated Blue Line: Metro could easily expand a Rosslyn Terminal into a new line to DC. A likely path would take the line under the river to Georgetown and then east into the downtown core.

In addition to the 26 trains per hour (TPH) running between Rosslyn and Downtown on the Orange/Silver subway, an a separated Blue Line to Georgetown and into downtown would allow 12-16 additional trains to cross the Potomac at Rosslyn.

This would increase the number of trains running between Virginia and DC per hour during the peak from 40 to 52.

However, because the Blue Line shares with the Yellow Line, the new subway across downtown Washington would only be able to operate at roughly half of its maximum capacity. That's probably fine in terms of ridership for a while (and off-peak for much longer), but in order to get the full potential out of the new line, it would need to be separated from the Yellow Line.

A separated Blue Line could also allow for more service on the Green Line through the Waterfront or Capitol Riverfront areas, which are quickly adding jobs. Metro could get some additional Green capacity by shifting some Huntington trains to the new Blue subway via Rosslyn (a sort of reverse Rush Plus).

Shifting some Huntington trains to run through Rosslyn would not increase the number of trains crossing the Potomac beyond what could cross under the first separated Blue Line scenario, but it would enable more service on the Green Line.

Two new subways?

What about both a separated Blue Line and a separated Yellow Line? Two new subways in the core would be very expensive. But if Metro wants to maximize the capacity on its system, it has to separate each line in the core.

One way to do this is to build a new terminal for the Blue Line at Pentagon. The Blue Line could have its own platforms, and trains from Franconia-Springfield (now all colored Yellow, or perhaps a new color) and Huntington would all cross the 14th Street bridge.

This would also have the advantage of reducing the amount of interlining in the system. With the lines no longer sharing with each other, delays wouldn't cascade across multiple lines if a train were to break down or some other mishap were to occur.

But the real issue is being able to have the flexibility to balance trains across the different lines. Right now, the Blue and Orange must be balanced based on ridership demand, as do the Green and Yellow. The problem is that Metro is bumping up against the absolute capacity of both subways.

With just a separated Blue, there would still be demand for a direct trip across the 14th Street Bridge. And once that demand outstrips Metro's ability to provide supply, Metro won't be able to do anything (because the Yellow shares with the Green). With just a separated Yellow, service between Pentagon and the western side of downtown is constrained by demand for the Orange/Silver.

At some point in the future, if Metro keeps growing, it may become necessary to build the other separated line. With both a separated Blue and a separated Yellow, the number of trains crossing the Potomac would increase to a maximum of 78.

Other improvements would probably be necessary to enable a full 26 trains per hour to run on the Green Line. It's not clear if the terminals at the end of each line could handle turning 26 trains each hour. Metro would probably need places for trains to turn around short of the terminals, like the pocket tracks at Silver Spring and Grosvenor on the Red Line. Alternatively, Metro could look into rebuilding the terminals, Branch Avenue and Greenbelt, with more capacity.

It's hard enough to say if we can get one new subway by 2040, given the funding picture today. But a second new subway might be in the cards farther down the line, and now is the time to start planning for it.

Last week, we talked about plans to give Metro the capacity it needs to get through 2025. What about beyond? The primary issue after 2025 will be cross-Potomac capacity.

Photo by the author.

Metro will likely choose to build, hopefully by 2025, either a new terminal for the Blue Line at Rosslyn that doesn't share tracks with the Orange or Silver Lines, or a "wye" so trains from Vienna and Tysons can turn toward the Pentagon.

However, neither solution increases the number of trains that can cross the Potomac River. Metro will need to start planning for the next phase very soon, since it takes so long to plan and build transit. Also, Metro's plan beyond 2025 could influence which of the options (terminal or wye) it chooses for 2025. Let's look at how Metro might expand its core capacity starting with each of the 2 primary Rosslyn alternatives.

Post-2025 solutions that go with a Rosslyn wye

Without construction in the core, a Rosslyn wye alone can't add any cross-Potomac capacity. Metro could build a second wye at Pentagon, for trains from Vienna and Tysons to cross the 14th Street bridge. However, the 7th Street tunnel, which carries the Green and Yellow Lines through downtown, can't take any more trains.

Wyes at Pentagon and L'Enfant: If Metro builds a total of 3 wyes, at Rosslyn, Pentagon, and L'Enfant Plaza, it could fit a few more trains across the river. Trains from Arlington Cemetery could cross the 14th Street Bridge, then continue east onto the Green Line toward Branch Avenue.

This scenario would let Metro fill unused capacity in the system without building any new trunk lines. However, much of this new capacity would go on the Green Line south of Waterfront station. Customers wanting to get to the downtown area would have to transfer.

It would, however, significantly add service to the growing Waterfront and Capitol Riverfront areas. DC has zoned much of these areas for downtown densities, but instead of the 5 lines that serve downtown or 3 in the Golden Triangle, this area has just one. This option would beef up service there, though many of the people riding there would want to come from downtown, and this doesn't boost that connection.

To absolutely max out capacity, Metro would need to run a line, like the lime-colored line on the map above, from Franconia to Branch Avenue. It's not completely necessary, but it would allow more full use of the capacity.

Unfortunately, this would increase the amount of interlining in the system, because trains would be running across multiple lines. The complex scheduling it would take to run this sort of service pattern might actually lower the total number of trains Metro can run through a tunnel.

This scenario would increase trans-Potomac capacity from 40 to 52 trains per hour, or just to 46 TPH without the Franconia-Branch Avenue Line.

Pentagon wye and separate Yellow Line: Metro has talked about building a separate tunnel for the Yellow Line. It's not clear where it would go yet. It could run north along 9th or 10th Street, or it could run east toward Capitol Hill before turning north.

This subway would separate the Yellow and Green Lines. That would allow Metro to run additional Green Line service between Greenbelt and Branch Avenue, including more service between downtown and the Waterfront/Riverfront areas.

It would also allow more service across the Potomac by decoupling the Green and Yellow Lines. However, since the Yellow Line shares tracks with the Blue south of Pentagon, this new subway would not be used to its full capacity.

Metro could get some additional capacity by routing some trains from Tysons via Arlington Cemetery over the 14th Street Bridge and into the new subway, if it built a wye at Pentagon. This would increase service across the Potomac to 52 TPH. Without the line running from Tysons through Arlington Cemetery, that would drop to 46 TPH.

Splitting Yellow Line service: Another option Metro studied for the Yellow Line is a new tunnel through the Capitol Riverfront, past the Capitol, and north to Union Station. This would increase service at Union Station, a major bottleneck, and give riders two ways to get downtown from the Waterfront/Riverfront area.

However, a lot of the riders in Alexandria and southern Arlington don't want their train to go so far east. They want to get to the 7th Street corridor. Therefore, Metro studied the idea of splitting the Yellow Line, with some trains taking their current path through L'Enfant Plaza and Archives while others would go to Union Station.

This operating plan makes a lot of sense with the Rosslyn wye, because those trains can fill the "gap" left on the 14th Street Bridge by Blue Line trains running north toward Rosslyn. With a new path for some Yellow trains, there would be room to add more Green Line service.

This approach would allow 52 trains per hour to cross the Potomac.

Tomorrow, we'll look at another set of long-term solutions, which Metro might pursue if it builds a new Blue Line terminal and then can send the Blue Line across the river toward Georgetown.

When WMATA released its Momentum plan last week, it reopened the conversation about dealing with core capacity. By 2025, the plan seeks to address one of the biggest chokepoints in the system: Rosslyn.

Metro has to juggle service at Rosslyn, where the Orange and Blue lines merge entering the District from the west, because it faces a structural limit to the number of trains per hour (TPH) that any given section of track is capable of handling. That limit is 26 TPH, or about one train every 2.3 minutes.

The reason for Rush Plus last year was to deal with capacity issues at Rosslyn without undertaking any capital projects. Essentially, Rush Plus was a stopgap measure to get a little more capacity out of Metro. But Rush Plus hurt many Blue Line riders, and without major changes at Rosslyn, even Rush Plus won't be enough.

As ridership increases, Metro has to either find creative ways to move more people throughout the system, without crossing 26 TPH on any segment of track, or expand capacity.

At Pentagon, those same 10 Blue trains were passing through in addition to 10 Yellow trains. In total, 36 TPH were entering the District from Virginia during the morning rush via Rosslyn and Pentagon combined.

But this left some capacity unused. The Yellow Line bridge was carrying only about 40% of the trains it could carry. As you can see in the diagram below, there was also extra capacity in the Yellow and Green Line tunnel.

This map shows the frequency of service for every line during the peak period. Every track segment is the same width, corresponding to 26 TPH. If 26 TPH pass through at peak, it's "full" with colored lines; if there are fewer trains, there is black space.

After Rush Plus

Once Rush Plus took effect, those numbers increased slightly. At Rosslyn, the numbers are now 19 Orange and 7 Blue, which is still 26 trains per hour. But at Pentagon, in addition to the 7 Blue trains running via Rosslyn, there are now 13 Yellow trains. That means a total of 39 TPH are entering the District from Virginia during the morning rush.

Since the number of trains is the same at Rosslyn as it was before, Metro could have kept the number of Blue and Orange trains the same, and just added new Yellow trains. But adding trains from Virginia was only part of the equation. Metro was also attempting to address the severe crowding on the Orange Line and paving the way for the Silver Line. As a result, Metro traded some Blue Line trains for Orange ones.

When the Silver Line begins operating, some of the Orange trains will have to become Silver trains, in order to keep the total number passing through Rosslyn at 26 TPH.

Cross-Potomac capacity will be maxed out

One of the biggest constraints with Metro is getting trains between Virginia and DC. There are 2 Metro crossings of the Potomac: a tunnel for the Blue/Orange lines and a bridge for the Yellow Line.

Each of these crossings has a capacity of 26 trains per hour, for a total of 52. However, because the Yellow shares with the Green Line, the Yellow Line bridge can only carry 26 TPH minus however many trains per hour are running on the Green Line (at present, 12 TPH).

This means that there are 14 slots available for the Yellow Line to cross the Potomac. Right now, the Yellow Line is taking 13 of those slots during rush hour: 10 for trains running between Huntington and Mount Vernon Square and 3 for trains running between Franconia and Greenbelt.

When the Silver Line opens, Metro's plan will be to redirect one more Franconia train to Greenbelt. This will mean cross-Potomac capacity will be maxed out at 26 TPH through the Rosslyn tunnel and 14 TPH over the Yellow Line bridge, for a total of 40 TPH between Virginia and DC.

Through 2025, those 40 trains are probably enough. But there's another problem: now there aren't enough trains running between Pentagon and Rosslyn. Riders from south Arlington, Alexandria, and southern Fairfax have long waits to get a train to Rosslyn, the Orange and Silver corridors, or to reach stations like Foggy Bottom without a transfer.

How can Metro fix Rosslyn?

Metro wants to address the Rosslyn chokepoint soon. It's one of 7 capital items in the "Metro 2025 recommendations of the Momentum plan.

Planners haven't decided on a specific solution yet, but are studying 2 options. One would build a "wye" at Rosslyn, a track connection so that trains from Tysons or Vienna could turn south and head for Arlington Cemetery, and vice versa. The other option is to build a new station at Rosslyn with separate platforms for the Blue Line.

The wye at Rosslyn would also let Metro add rail service between the Blue-Yellow corridor and the Orange-Silver corridor. Some trains going through Arlington Cemetery would go toward downtown, as the Blue Line does today, while some trains would turn west and run through Ballston and Tysons.

This approach would likely mean a good deal of disruption for Orange and Silver line riders, since Metro would need to build new underground connections to the line between Rosslyn and Court House. It would also permanently limit the number of trains between Court House and downtown DC, because some of those slots would go to the Blue Line and the new north-south all-Virginia line.

But this would also give riders a one-seat ride from Tysons to Pentagon and points south. It would also build a little more redundancy into the system, allowing trains to divert to the south in the case of track work, a disabled train, or other disruptions.

The real issue, though, is that this project only allows for a small increase in the number of trains, and does not increase the number of trains between Virginia and the District. It also would mean that some trains wouldn't stop at Rosslyn, forcing those actually heading there to wait for a later train or transfer.

Under the wye scenario, the service pattern would probably look something like this: 14 Yellow trains crossing the 14th Street Bridge (4 of them from Franconia) each hour during the peak; 5 TPH on the Blue Line between Franconia and Largo via Rosslyn; 10 TPH on the Orange Line from Vienna into DC; and 11 TPH on the Silver Line from Tysons. This still adds up to 40 TPH between Virginia and DC. In addition, the wye would enable 5 completely new TPH between Pentagon and Court House.

A new Blue Line terminal at Rosslyn involves building new, separate tracks at Rosslyn, possibly in a new station next to the old one, that would become the new end of the Blue Line. Blue Line trains could stop and turn around without interfering with the Orange and Silver trains going to Foggy Bottom, and Blue Line riders could transfer to either direction of those trains at Rosslyn.

A new Blue Line station at Rosslyn would allow even more trains between Pentagon and north Arlington—12 TPH, compared to 10 for the wye.

It would require passengers to transfer to the Orange or Silver lines to get to downtown or west toward Ballston and Tysons. But it would also form the first step toward a separated Blue Line through downtown. If and when Metro is able to build that, it could simply extend the new tunnel under the Potomac and beyond. If WMATA thinks a separate Blue Line will be the long-term approach, this solution might be more attractive.

Another advantage to a Blue station at Rosslyn is that it reduces the amount of interlining in the system. That should have a positive effect on reliability, because a delay on the Blue Line won't affect the Orange or Silver lines, or vice versa.

Note that we don't know which trains will go to Franconia or Huntington under this or any other future plan, or how many and which trains will go to New Carrollton vs. Largo vs. turn at Stadium-Armory. Since all trains to those destinations come from the same track, it's not an operational issue, just a question of balancing simplicity with convenience and being fair to riders on each branch.

Transferring can be painless

If Metro does go with the new Blue Line station at Rosslyn, they can help make transferring painless by getting the design of the new station right.

Cross-platform transfers are more commonplace in some cities. Montreal, for example, has 2 in their Metro system, Lionel-Groulx and Snowdon. New York has many, especially between local and express services on each line.

A 4-track stacked Rosslyn station would allow passengers from an inbound Blue Line train to simply walk across the platform to board an inbound Orange or Silver train. To transfer from an inbound to an outbound, the passenger would just have to go downstairs or upstairs.

The station could look something like this:

A Rosslyn design with cross-platform transfers. Graphic by the author.

It would be more expensive, but in terms of simplifying riders' ability to transfer, it could be worth it to build a new Rosslyn station with 4 tracks.

On the other hand, such a station would cost more, and would disrupt all service through Rosslyn during construction, just as the wye would, while a separate station could avoid interfering with Orange and Silver service.

But any new station will be there a long time, and riders may regret making it more difficult to transfer. After all, many riders still suffer from the lack of a direct connection between Farragut North and Farragut West (a tunnel that Metro proposes to complete as part of their 2025 plan).

New Metro tunnels in downtown DC sound really cool (and expensive), but they're not what's most important about the "Momentum" strategic plan WMATA planners showed their board on Thursday. Rather, the crux of the plan is the smaller, yet very important, projects Metro needs for 2025.

Photo by woodleywonderworks on Flickr.

The capital improvements in "Metro 2025" come to about $6 billion, and include these 7 items:

The Momemtum plan also talks about some downtown tunnels in a future phase, "Metro 2040," but Tom Harrington, Director of Long-Range Planning for WMATA, emphasized in an interview that WMATA has not made any decisions about where specifically such tunnels would go, or which they want to build.

Rather, those sections are more general placeholders than anything else. While it's likely Metro needs at least one new tunnel to add capacity, WMATA can't even begin to plan for those tunnels until the elements of the 2025 plan get funding.

Given how long it takes to design, build, and fund transit in the United States, it's not too early to start talking about and building support around the elements of the 2040 plan. But what's more important now is laying the groundwork to enable those plans to go forward. That's the 2025 plan.

Harrington added that the $26 billion figure in the Washington Post's headline, which most other reporters subsequently focused on, isn't really the price tag for WMATA's plans. Rather, that covers the total cost of all transit projects the region's governments hope to build as well as future projects for WMATA.

As we discussed on Thursday, the plan also contains a lot of priorities for WMATA to improve its own operations. They include finishing repairs on the system, ensuring it's safe, devising better plans for communicating disruptions, making the system more "self-service," lowering costs and increasing efficiency, environmentally sustainable practices, and more.

The plan is not very detailed about these, and we look forward to hearing and discussing them more when there's more to understand.

Meanwhile, let's look more at the 7 capital items:

Photo by erin_johnson on Flickr.

100% 8-car trains: The original system's designers anticipated having trains of 8 cars, the full length of each platform. However, the system didn't need such long trains at the start, since the designers knew demand would grow over time.

They didn't build enough power stations and yard space to house all of those cars, anticipating that as the system grew, the local, state, and federal governments would fund the system's growth. That investment didn't continue much after the initial system was built, however. Today, Metro is overcrowded in many places, and needs the longer trains.

Core station capacity: The main transfer stations (Metro Center, Gallery Place, and L'Enfant Plaza), plus Union Station which is a transfer point between Metro and commuter rail or Amtrak, are jammed during rush hour. Metro needs to expand key spaces inside the stations and increase the numbers of escalators, elevators, and/or stairways between the different levels of the stations.

Image from WMATA.

WMATA's proposal includes pedestrian tunnels between Farragut North and West, and Metro Center and Gallery Place. The Farragut tunnel would reduce loading on the Red and Orange Lines where people have to currently ride to Metro Center to transfer, and the Metro Center-Gallery Place tunnel would let people avoid riding the Red Line one stop to transfer there.

Fix Rosslyn: This is the system's biggest bottleneck. We'll talk about this in part 2.

Turnbacks: Many subway systems have places where "gap trains" can wait to enter service in a busy section if trains get delayed, or places to push a disabled train out of the way. The Momentum plan isn't clear on where these would be, and Shyam Kannan, Managing Director for Planning, said WMATA is finishing up a study on this now.

In the past, WMATA planners have talked about adding pocket tracks north of Fort Totten and east of Eastern Market. A pocket track north of Fort Totten would also make it possible to run Yellow Line trains to Fort Totten during rush. Here's an explanation of why it's not possible to do that today; basically, they turn around on the main tracks, which takes too long to avoid delaying other trains at rush frequencies.

Communications infrastructure: The current "PIDS" screens in rail stations use very old technology dating back to Metro's early years. According to Kannan, during a service disruption, someone has to manually modify the information in the computer system to get the PIDS to work properly. They want to replace this whole system with a more modern one that doesn't have the flaws of the old.

This project also will involve systems to help riders get real-time bus and train predictions, Kannan said. Metro would like to place large screens, perhaps 4 by 6 feet, in many rail stations and busy bus stops to tell riders about the locations of trains and buses, as well as information about other modes like commuter rail and commuter buses. Better apps for smartphones and tablets, as well as open data to help other developers make their own tools, are also part of this piece of the strategic plan.

Bus priority corridors: Let's not forget buses. As we've talked about many, many times, making the buses more efficient, with features like "queue jumpers" to bypass congested areas, is an inexpensive way to improve transit and could even save money. If a bus can travel its route more quickly, you can have the same bus frequency with fewer buses and drivers, or more frequent service with the same numbers.

WMATA has identified a set of corridors ripe for optimizing bus service, but it needs more cooperation from local jurisdictions, which control the roads, signals, and bus stops, to make it happen. Some early elements are in the works; DC is planning bus lanes on H and I Streets past the White House, for instance.

More buses and a bus garage: A lot of bus riders wait longer than they should have to. We should beef up service on busy lines and in key places, like east of the Anacostia, which need better connectivity.

Also, WMATA needs to replace its aging garages in DC with a new one somewhere; Walter Reed was a promising spot, but Muriel Bowser and Vincent Gray blocked the idea; most recently, they have apparently been eying the Armed Forces Retirement Home, at North Capitol and Irving.

These are not in the region's plans today

These 7 items are extremely important for mobility in our region. They aren't just things that would be nice to have, but necessities if we don't want terrible overcrowding and delays.

However, these items are still not in the Constrained Long-Range Plan (CLRP), the list of transportation projects each jurisdiction gives to the Transportation Planning Board to staple together into a regional plan. (DC just proposed adding the I Street bus lane, and already had H Street in there).

As the TPB explains:

The CLRP (Financially Constrained Long-Range Plan) includes all "regionally significant" highway, transit and High-Occupancy Vehicle (HOV), bicycle and pedestrian projects, and studies that the TPB realistically anticipates can be implemented by 2040. Some of these projects are scheduled for completion in the next few years, while others will be completed much later.

That means without action by regional leaders, we could get to 2040 and still have no more 8-car trains, the same and even worse Rush Plus crowding problems, terrible jams at transfer stations, buses stuck in even more traffic, and no room to park buses to expand service.

These improvements are basically necessary to keep Metro running efficiently over the next decade and to set the stage for future expansion. But it will not be easy to build these projects unless regional leaders are able to work together to secure funding for Metro's future.